Early hemodynamic changes in experimental intracerebral hemorrhage

Early aneurysm surgery: a 7 year clinical practice report

One hundred and fifty patients with intracranial aneurysms, operated on consecutively in the early stage in our department, were re-evaluated retrospectively. Seven surgeons operated on 159 aneurysms in 150 patients. Seventy-nine percent of the patients were in grades I-III (scale of Hunt and Hess), 21% in grades IV-V. Seventy-one percent had a severe haemorrhage (classification of Fisher et al.), 21% had an intracerebral haematoma. Intraoperative CSF drainage was an almost indispensable tool while postoperative external drainage did not prove to be helpful in preventing vasospasm and/or hydrocephalus. Induced hypotension was abandoned in favour of temporary clipping. Thirteen percent of the patients suffered a permanent or fatal immediate postoperative deterioration, while 11% developed delayed neurological deficits. Five percent were related to vasospasms alone, they were all transient. Five percent had vasospasm combined with other complications. One of them had permanent and the other one fatal deficits. One percent deteriorated due to embolism or occluded vessels. The results improved with the introduction of the calcium channel blocker nimodipine, induced hypertension and transcranial Doppler sonographic control of the vasospasm. Patients in good preoperative condition had a good early outcome in 69%. The result was fair in 21% and poor in 4%, while 6% of the patients died. In the poor condition group 22% of the patients made a good, 13% a fair, and 59% a poor recovery, 16% of whom died.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute injury to the central nervous system

Central nervous system (CNS) trauma is divided into brain and spinal cord injury. A basic understanding of the pathophysiology of CNS trauma helps the practitioner more accurately evaluate, treat, and prognose cases of CNS trauma. The progressive nature of CNS injuries and the contribution of microvascular ischemic are explored.

Serial changes in focal hyperemia associated with hypertensive putaminal hemorrhage

Seventeen separate xenon-enhanced computed tomographic images were performed in seven patients with hypertensive putaminal hemorrhage. Regional cerebral blood flow maps were then computed and assessed. All patients were categorized as being of good recovery potential, with moderate-sized hematomas, and all were treated conservatively. The regional cerebral blood flow assessments were scheduled within 4 days after, 2 weeks after, and less than 25 days after the ictus. The initial decrease in hemispheric blood flow ipsilateral to the side of the hematoma was calculated as the ratio of ipsilateral to contralateral hemispheric blood flow and was correlated with the size of the hematoma; that is, the larger the hematoma, the greater the decrease in the ratio of ipsilateral to contralateral hemispheric blood flow. The decrease persisted for 1 month. The mean of the ratio at 2 weeks after onset was 70%, the lowest during follow-up. All cases examined within 4 days after onset demonstrated perihematomatous focal hyperemia, or "luxury perfusion," which accounted for the delayed decrease. The same tissue that had previously shown hyperemia showed decreased regional cerebral blood flow 2 weeks after onset. Our results demonstrate that the luxury perfusion syndrome caused the secondary brain damage even in the cases that were in relatively good condition. The feasibility of treatment can be assessed by considering these results.

Pathophysiology of delayed ischaemic dysfunction after subarachnoid haemorrhage: experimental and clinical data

Cerebral arterial spasm from subarachnoid haemorrhage (SAH) may be associated with the clinical syndrome of delayed cerebral ischaemic dysfunction, but the two conditions are by no means synonymous. Patients in good clinical condition may be seen with severe vasospasm and vice versa. A variety of mechanisms may be responsible for the neurological dysfunction: current evidence indicates that most of these mechanisms produce a reduction in cerebral blood flow (CBF). In the early stages after SAH, there is a loss of autoregulation so that reduction in cerebral perfusion pressure (CPP) may produce ischaemia. This fall in CPP may be due to elevated intracranial pressure (ICP) or reduced mean arterial blood pressure (MABP). Delayed cerebral ischaemic dysfunction following SAH is a clinical syndrome which may also be caused by re-bleeding, hydrocephalus, dehydration, reduced cardiac output and/or blood pressure, hyperglycemia or epilepsy. Experimental evidence has indicated that at the time of an intracranial haemorrhage there is a profound and extensive focal ischaemic insult. The severity of the ischaemia depends upon the nature, size and rapidity of onset of haemorrhage. The focal ischaemic lesion around an intracerebral haemorrhage becomes smaller with the passage of time and is the result of two interacting phenomena: a) The physical properties of the haemorrhage result in increased local tissue pressure around the lesion. This produces squeezing of the microcirculation and focal ischaemia. b) Vasoconstrictor elements in blood produce spasm which may further reduce CBF, sometimes even remotely from the lesion. Treatment of delayed ischaemia therefore depends upon its cause.

Experimental intracerebral mass: time-related effects on local cerebral blood flow

Cerebral blood flow (CBF) was measured at different times during the first 150 minutes following an experimental space-occupying lesion produced with a 50-microliter microballoon in rats. Local CBF was measured with the carbon-14-labeled iodoantipyrine quantitative autoradiographic technique. A region of local ischemia developed around the mass, while the remote effects of the mass were minimal. The focal ischemic lesion enlarged with time, and simulated removal of the lesion within this design did not alleviate the ischemia.

Effects of experimental intracerebral hemorrhage on blood flow, capillary permeability, and histochemistry

Experimental intracerebral hemorrhage has been shown to cause extensive cerebral ischemia. This study was performed to ascertain the time course of these changes and also to examine the type of brain damage that may occur under such circumstances. Halothane anesthesia was induced in rats, and 25 microliter autologous blood was injected into the caudate nucleus; the effects were studied with autoradiographic measurement of local cerebral blood flow and capillary permeability, and also by light microscopy and histochemical techniques. Blood flow returned to normal or to slightly increased levels within the first 3 hours, and ischemic levels of flow were found to persist only to a marginal degree beyond 10 minutes after the lesions were made. Capillary permeability was maximum during the first 30 minutes after the hemorrhage and diminished with time. Structural evidence of ischemic damage was localized to the cortex overlying the hemorrhage, but was not seen in the caudate nucleus. Nevertheless, histochemical investigation did reveal an area of disturbed enzyme function in the striatum. This finding of biochemical disturbance without structural evidence of ischemic damage reveals that there is an area around the hematoma that, although demonstrating disturbed function, does not show structural damage, and the milieu of this partially injured brain may be implicated in the delayed development of the ischemic brain damage that follows intracerebral hemorrhage in man.